Intensifier



May 26, 1953 B. H. SHORT ET AL 2,640,174

INTENSIFIER Filed Oct. 30, 1950 ril-b T0 D/s Te /Bu T02 CAPA'/TY AT GnP 3105 CAPACITY PROV/DED e Yan/.L 35

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/N vE-N rola s ffl/veuf 6. Laarzen/nsf@ Taf/e A Tron Ne Ys Beau/rs SHORT mm s Patented May 26, .1953

IN TEN SIFIER Brooks H. Short and Ar gyle G. Lautzenhiser, An-

derson, Ind., assignors to General Motors Corporation, Ware Detroit, Mich., a corporation of Deia- Application October 30, 1950, Serial No. 193,012

(Cl. S15- 60) 10 Claims.

This invention relates to spark intensiliers for ignition systems used on automotive vehicles. Spark intensier is a term applied to a device which provides a relatively wide spark gap in series with a gap of a spark plug for the purpose of withholding application to the spark plug gap of the secondary voltage of an ignition coil until said secondary voltage has reached a value such as to cause a spark to jump across the spark plug gap, although that plug may be fouled by carbon deposit. In spark intensiers, known heretofore, the secondary voltage is caused to attain a value substantially higher than that required to cause a fouled plug to fire.

An object of the present invention is to provide a spark intensifier which will cause a fouled plug to fire at a secondary voltage substantially less than that required heretofore by a conventional spark intensifier. In the disclosed embodiment of this invention, this object is accomplished by augmenting the capacity of the spark plug gap by acapacity provided bya grounded metal shell surrounding the spark plug electrode so that the total effective capacity of the spark plug gap is much larger in value than the capacity of the intensifier gap whereby the impressed secondary voltage is so divided that, prior to firing, the voltage impressed at the spark plug gap is small as compared with the Voltage applied at the intensifier gap. By thus dividing the voltage in inverse proportion to the capacities of the gaps, the leakage at the fouled spark plug gap is low in value and coil energy is not dissipated to any material extent during the time required for rise of secondary voltage to the value for current to jump to the intensifier gap. Therefore, the attained secondary voltage is a relatively small amount in excess of that required to jump theintensier gap.

A further object of the invention is to provide stability of operation of the intensier and this is accomplished by means provided for irradiation of ultra-violet rays at the intensifier gap.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a side view of a spark plug with the present intensier attached thereto.

Fig. 2 is a sectional view on line 2-2 of Fig. 1.

Fig. 3 is a View in the direction of arrow 3 of Fig. 1.

Fig. 4 is a diagram of capacity circuits effecting the operation of the intensifier.

AIn the drawing, a spark plug l .includes a metal shell having a threaded portion |2 to be received by a threaded hole in an engine cylinder head, not shown. The shell supports a porcelain insulator I3 which supports an electrode wire I 4, the lower end of which is spaced from an electrode Ma attached to the shell to provide the spark plug gap referred to hereafter as gap #2. The electrode wire I4 is attached to a terminal I5.

An intensifier 23 comprises a porcelain body 2| which includes a tubular portion 22 surrounded by a metal shell 23 having a hexagonal ange 24 which ts snugly around the hexagonal portion Ila of the shell I, thus providing a support for the intensifier. The portion 22 surrounds the upper portion of the spark plug and a socket 25 which engages the spark plug terminal I5. The socket 25 is attached to a rod 26 which extends through the body 2| and terminates in an electrode 2l located in a recess 28 of the body and in alignment with the end portion of an electrode 29 provided by a rod 30 which extends through the body 2l and is connected with a terminal 3| for making connection with a wire connected with the ignition distributor which distributes sparking impulses from the secondary winding of an ignition coil. A screw 32 threaded thru the body 2l secures the rod 30 in position. The gap between the electrodes 21 and 29 is known hereafter as gap #I which is the main intensier gap.

The body 2| supports a rod 33 secured by a screw 34 threaded in the body. The rod 33 extends within the recess 28 and is provided with a point spaced from the electrode 29 and located slightly above its lower end. The gap between rod 33 and electrode 29 provides what is known as gap #3. The outer end of rod 33 is attached to a ball 35.

To minimize the tendency for leakage on the surface of the body 2| it is provided with grooves 36 and 31.

Referring to Fig. 4, the capacities effecting the operation of the intensier may be considered as being four in number and they are arranged in parallel circuits between terminal 3| and ground. Capacity CI is the capacity at gap between the electrodes 2l and 29. Capacity C2 is the capacity provided by the shell 23 plus the capacity at gap #2. Capacity C3 is the capacity at gap #3. Capacity C4 is the capacity of the ball 35 and the rod 33 with respect to ground.

Assume that 14.5 kv. secondary voltage is required to cause a spark to jump across the spark plug gap 2. If the spark plug is fouled by accumulation of carbon deposit, this deposit provided a path for leakage oi secondary voltage so that it never attains 14.5 kv. to fire the plug. An ordinary spark intensifier which provides a Wide gap in series with the distributor and the spark plug serves to withhold secondary current flow until the secondary voltage is at a value much higher than 14.5 kv. in order that there will be a voltage sufficient to cause a spark at the gap.

In order to prevent the required supply voltage from increasing to a value substantially higher than required to re the plug, the capacity of the spark gap 2 is augmented by the capacity provided by the shell 23 to provide a total capacity C2 much greater than capacity yC! of the intensifier gap 2. Therefore the share orf available voltage required by capacity C2 is small as compared with the share required by capacity C i. For example, if the ratio of capacities C l' and 'C2 is about 2/ 12.5, when supply voltage has vincreased to 14.5 kv., the voltage impressed on gap I will be .12.5 kv. and the voltage impressed on gap 2 will be 2 kv. During the increase of voltage at gap 2 to 2 kv., leakage of lenergy is .relatively small during the time required to increase the `voltage to 2 kv. When voltage impressed .on gap l has increased to 12.5 kv., this gap breaks down and instantly the voltage at gap 2 is increased to 14.5 kv. and the spark plug fires.

If the ratio of capacities Cl and C2 were nearly uni-ty as in the case of an ordinary spark intensifier the required voltage for the intensiiier and the plug would approach two times the plug voltage, and in the example a potential of 29 kv. would be required. Increas'ng the Icapacity of C2 with respect to' Cl lowers the required voltage for the combination, as has been indicated.

The relation of capacities C3 and C4' 4is such that sparking at gap 3 called the teaser gap occurs before sparking at the intensifier gap i. Sparking at gap 3 irradiates intensifier gap l with ultra-violet rays so that the intensiiier gap breaks down at a consistant voltage, for example 12 to 13 kv. I- the teaser gap .3 were not present, the voltage 'at which gap i would break down might vary between 12 and 30 kv. Thus the teaser gap 3 stabilizes the operation of the present intensiiier.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms u might be adopted.

What is claimed i's as follows:

1. An intensiner adapted for use with a spark plug comprising conductors providing, in series with the spark plug gap, a than the spark plug gap; a non-conducting body supporting the conductors; means attached to the body for raising the capacity of the spark plug gap to a value of a plurality of times greater than the capacity of the intensiiier gap whereby the plug-iiring voltage required for the gap combination is substantially less than otherwise; a teaser gap provided by an additional conductor supported by said body and having one end spaced from one of the conductors at the intensifier gap; and a metal body attached to the other end of the additional conductor and having dimensions such that its capacity with respect to ground is greater than the capacity of the teaser gap.

2. An intensifier adapted for use with a spark plug comprising, a body of insulating material having a recess at each end; a conductor extending axially through the body and providing .a spark plug terminal in one recess and a sparking terminal in the other recess; an adjustable gap ofV a length greater electrode carried by the body having one end extending into the said one recess to provide a relatively large spark gap; a second adjustable rod carried by the body and having one end extending into the said one recess, said end being slightly above the lower end of the electrode to provide a small gap; a metallic sleeve having one end secured to the body about the recess containing the spark plug terminal and having the other e-nd formed so as to iit snugly around and in direct contact with metal member of the spark plug.

3. An intensifier adapted for use with a spark plug comprising, a terminal support comprising vabody of insulating material having a radially disposed notch at one end extending inwardly from the periphery of the body and having an axially disposednpocket extending from the other end of the body, said recess and pocket being separated .by a partition wall; an electrode fixed in the partition wall aznd having one end exposed in the recess and havingy the other end exposed in the pocket, said pocket adapted to receive one end vof a spark .plug for electrical connection with its insulated electrode; a plurality oi rrods supported by the body to which an electrical conductor is adapted to be connected to one of the rods, each rod having an end extending into the recess and spaced from each other to provide a relatively small gap and spaced from the electrode to provide a relatively large gap, and means to minimize the electrical leakage on the .surface of the recess and the exterior of the body, said means comprising a plurality of relatively deep grooves in the marginal walls of the recess and on the exterior of the partition wall; and a metallic sleeve having one end secured to the body and having the other end adapted to receive and rest on a metal. part of the spark plug to support the body in correct position with respect to the plug.

4. An intensifier adapted for use with a spark plug having a centrally disposed electrode wire; a body of insulating material having a tubular portion on its lower lside for the reception of the electrode wire and having a recess on its upper side; a conductor extending axially through the body having one end exposed within the recess and having the other end exposed within the.

tubular portion; a metallic socket electrically connected with the conductor adapted to engage the electrode wire of the spark plug; a detachable terminal supported by the body having one end adapted to be connected with a wire adapted to be connected with a distributor which distributes sparking impulses from a secondary coil of an ignition coil, said terminal having its other end extending into the recess of the body and spaced from the conductor; a detachable metallic rod supported by the body and having an end located within the recess and above the terminal end; and a metallic sleeve having one end fitting snugly around the tubular portion of the body and having its other end formed so that it will receive a metallic shell of the plug.

5. In combination; a body of insulating material having a recess at one end extending inwardly from the periphery of the body and beyond the axis of the body and having a pocket at the other end extending axially from the other end thereof said pocket having a contour for receiving an insulated electrode of a spark plug; a conducting rod embedded in the body and having its opposite ends exposed in the recess and the pocket; a split sleeve carried by the electrode for making electrical connection with the electrode; adjustable conducting rods supported in the side wall of the body and extending into the recess above the electrode and having their ends spaced to provide a relatively small gap between the rods and a relatively large gap between the ends of the rods and the electrode; and a metal sleeve having one end fixed to the body and having the other end adapted to make direct contact with a metallic member of the spark plug and assisting to support the sleeve in proper position.

6. An intensifier adapted for use with a spark plug having a centrally disposed electrode adapted for connection With-a cable, having its upper end provided with circular beads comprising a non-conducting body having one end provided with a recess extending radially inward from the periphery of the body and having a tubular pocket extending upwardly from the other end for enclosing the electrode; a rod embedded in the body and having its opposite ends exposed respectively in the recess and pocket, a split sleeve carried by the rod for the reception of the ribs of the electrode; a pair of adjustable rods supported by the body; each having one end located within the recess and spaced to provide a relative small gap therebetween and a relative large gap between said ends and the electrode; and a metallic sleeve having one end secured to the tubular pocket portion of the body and having the other end formed for seating engagement with a metallic part of the plug to maintain the sleeve in proper position.

7. An intensier comprising in combination a body of insulating material having an axial recess at one end adapted to receive an insulated electrode of a spark plug and having a side recess at the other end, said body having a spaced radial opening for receiving a pair of adjustable rods to be inserted from the outside and converge toward each other within the side recess to provide a small gap therebetween; a conductor carried by the body and having its opposite ends exposed in the recesses, said end of the electrode exposed within the axial recess being adapted to engage the electrode of the spark and having the other end exposed within the side recess spaced from the rod ends to provide a relative large gap between the electrode and the ends of the rod; and a metal sleeve having one end attached to the body around the axial recess and having the other end formed so as to seat on and in direct contact with a metal part of the spark plug.

8. An intensifier adapted for use with a spark plug which includes a central electrode which forms a spark gap at one end thereof with a portion of the body of the plug comprising, an insulating body adapted for mechanical connection disposed in spaced relation to the upper end of said electrode, at least one of said electrodes being spaced from the conductor a distance greater than the spark gap in the plug.

9. An intensifier adapted for use with a spark plug which includes a central electrode which forms a spark gap at one end thereof with a portion of the body of the plug comprising, an insulating body adapted for mechanical connection with a spark plug; a conductor in said body electrically the center elecwith a spark gap,

BROOKS H. SHORT. ARGYLE G. LAUTZENI-IISER. References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,203,264 Quevedo Oct. 31, 1916 1,417,871 Wackwitz May 30, 1922 1,447,812 Otto Mar. 6, 1923 1,477,119 Graf Dec. 11, 1923 1,518,248 Broluska Dec. 9, 1924 1,798,789 Gale Mar. 31, 1931 

